


Nights of Knights of Seiros

by LuxrayOnAO3



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Casual Sex, F/F, F/M, Futanari, Partner Swapping
Language: English
Status: Completed
Published: 2021-02-09
Updated: 2021-02-09
Packaged: 2021-03-14 18:53:57
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,167
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29300700
Author URL: https://archiveofourown.org/users/LuxrayOnAO3/pseuds/LuxrayOnAO3
Summary: Catherine and Shamir have an understanding. Just so you know.
Relationships: Catherine/Rhea (Fire Emblem), Catherine/Shamir Nevrand, My Unit | Byleth/Shamir Nevrand
Comments: 2
Kudos: 11





	Nights of Knights of Seiros

A knock came at the door. A book was set aside -- the blankets rustled; the door creaked open at a pull.

Shamir, Knight of Seiros, clad in dark-emerald half-jacket and coal-black corset, stood in the doorway; the very picture of lean, feminine death.

The woman leaned up against the jamb of the dormitory’s door, close to her visitee, her eyebrows quirking only slightly upward as Byleth opened the door and looked at her, the door slack in his hand.

“Shamir?”

“Hey, Professor,” Shamir said, her expression stern and unreadable as was her usual wont; arms folded across her chest, quite plainly looking him in the face. “Wanna fuck?”

Byleth blinked, a sputtering sound emanating from behind him. He strongly resisted the urge to look behind him.

“Hmph! Is that the case, then? Y-You mortals cannot be helped from your urges,” Sothis sputtered, red in the face, unseen to both of them. “Well -- well, you can take this one alone, Byleth!”

With that, there was an inchoate swirling sound, and with that requisite bizarre sense of internalisation, Sothis took herself off to wherever Sothis took herself to within him.

Byleth looked at Shamir, the woman now looking directly at him, waiting.

“Just say if you don’t want,” Shamir offered, already making to walk away. “Unless you’d rather sit inside all evening. By yourself.”

“Wait,” Byleth blurted, and Shamir turned her face back toward him.

“Aren’t you,” Byleth said, hurried, “I mean, you and Catherine--”

Shamir broke out into a short, cursory laugh.

“Huh. Catherine’s gone off to serve her higher calling,” Shamir said, answering his question as plainly as though it were a topic about the weather. “Want to come keep me company for the evening?”

Thoughts swirled through Byleth’s head. Shamir was attractive, lean, dark, and interested. She stood a foot from him, the look in her eyes that kind of smug yet dispassionate amusement she found in most everyone else she ever spoke to.

The way she leaned, her breasts jutting out from within her jacket, slim waist constrained by the corset, her dark hair falling around her face alluringly; Shamir’s whole figure was easy on the eyes, and here she was propositioning him.

Sorry, Sothis.

Byleth swallowed his tongue, smiling as best he could.

“Sure,” he smiled -- and that smile wasn’t much to impress the assassin, given the way Shamir smirked.

“Good boy, Byleth,” she said, darkly. “Come with me.”

* * *

If Byleth had a heartbeat, it was for sure beating now. Walking in the night with Shamir… they were both faculty, but shame threatened to show its face upon his.

Shamir strode confidently forward, nonplussed by any of it.

“Are you sure about this?” Byleth asked, a heat in his face, in his core; nobody had propositioned him before, and he wasn’t sure of the etiquette.

“If you are,” Shamir said, unceasing, not looking back. “Look, Cat’s gone off to our Archbishop.” Then she stopped, looking back at the young professor. “You want to or not?”

“I… Sure,” Byleth said. Shamir was, after all, cute too -- “Why me, though--”

Shamir shrugged, leading Byleth onward.

“Catherine and I are partners. She won’t turn down Rhea -- that’s fine, I know the deal. Catherine does, too. So she’s not around, and I’m in the mood. You’re young and cute. It doesn’t need to be awkward.”

Byleth hesitated. Shamir was cute, too, yes, but this sudden interest from one of the faculty members was, well, it was new, and surely one would say yes, unless you were interested in one of the students, so--

“Sure,” Byleth smiled, a tenth of a smile reaching to his lips. He closed the distance to Shamir, his hand going for hers--

“Please,” Shamir snorted, pulling hers away. “We’re not like that. We’re going to fuck.”

Byleth pulled his hand back, near-chastised, unsure what to think.

“Don’t sulk, Professor,” Shamir chided. “Come on. Let’s fuck. In Cat’s bed.”

* * *

Shamir banged at the door, and it swung open with a creak, a cluttered apartment revealing itself within. It was akin to Byleth’s rooms, only near twice the size and in a state of mild chaos.  
The woman gestured him in, and Byleth slid past her; down a step and two before the door slammed behind him, and Shamir skipped down the stone steps to follow.

“Hmph. Almost expected you to chicken out, on the walk,” Shamir said. “You’re cute, you know. You don’t have to say yes if you’ve got eyes for one of your little students.”

Byleth felt his pulse quicken. “Well, so are you. And no, that’s not the case.”

Shamir shrugged. “OK. Well, we’re in my quarters. Still want to back out or shall we quit wasting time?”

“What was wrong with my room?” Byleth said, Shamir already walking away towards the bedchamber.

“Too small,” she called back. “We can’t go in just a single bed.”

* * *

Byleth didn’t know how to kiss. Shamir did.

“Stop messing about and put your tongue in my mouth,” Shamir grumbled, pulling back briefly. “We both want it. Stop treating me like I’m gonna break.”

They kissed again; this time, with the goading, Byleth’s tongue slipped into Shamir’s mouth, and that elicited a reaction, as the older woman eagerly sucked at his tongue, the two of them rapidly getting short of breath.

“That feels really good,” Byleth blurted, as they broke apart, before clashing together again. This time Shamir drove her tongue in search of his, pushing past his teeth towards his throat, and the man returned the favour until they could stay connected no more.

“Hmph,” Shamir panted, “alright, I’ll concede you can kiss worth a damn, once you started trying.” The woman quickly reached up, throwing off her jacket and beginning to loosen her corset. “No -- don’t get up. You’ll have no idea about this. Let me get it off and you can show me what else you’ve got.”

A few interminable moments of fiddling with hidden laces, and the black corset came off. Byleth felt himself immediately begin to harden under her as her bare breasts and stomach came into view; large, round mounds with large nipples filled his vision, and his hands immediately snaked to her soft, inviting waist.

“Mmm,” a noise of approval meeting his initiative. “More. These girls aren’t going to touch themselves.”

* * *

Shamir’s partner was busy with her sacred duty.

Catherine felt her knees sink into the plush white woolen carpet of the Archbishop’s chambers, all niceties past.

“I am so grateful you attended me tonight,” Rhea cooed, soothing, her hands on Catherine’s bare shoulders. The two of them were unclothed, Rhea’s heavy breasts inches from the Knight’s face, heavy-set and downward in opposition to the woman on her knees.

Rhea’s Knight, Catherine, leaned forward, and gave Rhea a slight kiss on the stomach.

“So am I, Lady Rhea,” Catherine began, before a tongue lolled out, wrapping around the head of Rhea’s cock. Her mouth followed, and Rhea shuddered, a wave of warm, wet pleasure suffusing her.

Rhea’s cock was unusual, large, teasing. Catherine had reacted with shock, but now it was a matter-of-course. Rhea’s ancestry shone through in this particular regard, and ensconced within her Knight’s mouth was a flared, draconic member. More wide toward the base, the backside littered with small, spiny ridges; Catherine served her Archbishop as best she could, and her mouth quickly worked as far down Rhea’s dick as she could. The texture and the size -- Catherine could feel it scraping her tongue and the ridges of her palate; just what she wanted, and the feeling of Rhea’s cock in her mouth never failed to make the Knight redouble her efforts.

It was a long standing ritual, between the two. Catherine, on her knees, Rhea’s dick in her mouth and a pair of soft hands in her two-toned hair; Rhea, thrusting into the woman’s soft, welcoming mouth, the Archbishop’s lips doing that lips-parted, heavy-blushed, ever-so-satisfied moan.

“Oh, Catherine, my servant, you are so good, as always, my child,” Rhea cooed, her hands deep into Catherine’s hair, the slight tugging urging the woman further onto her cock. “You are such a good Knight to service me so, aren’t you? I’m so grateful, Catherine. So grateful.”

Catherine moaned into Rhea’s flared cock, that praise from Rhea so good-- and Rhea moaned slightly too; chest heaving, she clamped her thighs around her Knight’s face, not wanting to finish quite yet.

“Such a good girl you are, Catherine,” Rhea moaned, and at that, her moan was reciprocated. Catherine urged herself deeper, to swallow more of Rhea, and a wet, choking noise was Rhea’s reward.

“Glc-glrcc--ugchc-”

“Mmm-- Goddess, Catherine, yes, just like that--”

Catherine couldn’t hold back now, hands snaking up to Rhea’s hips, her mouth and throat now just utterly subservient to Rhea’s outsized cock. The ridges and bumps scraped against Catherine’s tongue and the roof of her mouth, stifling her from breath; she didn’t care -- it felt so good, Lady Rhea wanted it, Lady Rhea--

“Yes, Catherine, oh, Catherine, my Knight, my Knight of Seir- my Knight--”

Every word drove Catherine’s needs higher, the need to service the Archbishop conflicting with the need between her legs. But touching herself wouldn’t do. She’d wait for Rhea to grant her that when she’d decided her Knight was worthy.

Catherine bucked with her mouth just around Rhea’s cock as she came, and Rhea came with a loud moan in her own bed, moaning incoherently as her favoured sucked her down, Catherine willingly swallowing as Rhea erupted within her mouth. Rhea bucked for half a minute, odd physiology no problem to Catherine; the woman around her cock swallowed eagerly, and Catherine felt the salty mess hit the back of her throat, only too keen to put it away.

Eventually Catherine broke back, and it was short of breath, her cheeks blushed, her hair a mess; she looked at Rhea’s messy face with a wink.

“More, Archbishop,” Catherine smiled, her lips stained. “I want more."

* * *

Shamir was nude, lithe, eager, and now kissing Byleth with an intensity he nearly could not bear; their mouths were one, and neither of them wanted to break away.

Her lips -- that lip gloss, so subtle in her face, now making his lips and tongue sticky and needy -- they were all over him, and he was deeply hard under her atop of him.

Her breasts were coated by him; Shamir had moaned as he’d treated her to his tongue, and the woman was wet over him, her nipples hard and peaking.

Shamir broke back, her fringe falling into her face.

“How the hell do you know how to do that,” she panted, toned muscles over her body twitching, but with enough stamina to see this thing through. She grinned at Byleth, their faces an inch apart. Okay, you got the message. Shift up here and fuck me.”

Byleth didn’t need much of an invitation. Shamir -- slim waist, wide hips, slim thighs, nimble, toned. Neatly trimmed bush inviting his cock. He ached, and as he took himself in a hand, Shamir’s arching hips guided him in.

“Good boy,” she sighed, sinking onto his cock. “Shit-- it’s been too long--”

Byleth exalted in the feeling of her, her warmth squeezing against his cock almost too much to bear; but as he grabbed Shamir’s hips and let the woman ride him, they found a mutual rhythm to the benefit of each.

“G-Goddamnit,” Shamir moaned, her hips rolling on his cock, the penetration of his length too much given the time she’d spent since taking someone like this. “F-Fuck, Byleth, f-fuck!!”

“Take it, Shamir,” Byleth panted with a new intensity, seeing her desperation. “Take me. Take me and come, if you want, I’m close, so make me-- come all over this dick! Come whenever you want!”

Gasps filled the air, the assassin riding the professor’s dick, short, frenzied cries filling the air.

“No, no, no, you can’t make me cum this quick, f-- fuck, Byl- Byleth- Not even Cath--”

After that, it was too late. Shamir rode him on top even as Byleth worked at her hips. She was right; it’d been too long since she’d taken anything like this, and as Byleth’s cock worked at the deepest parts of her, Shamir knew she was utterly undone.

“By-B-Bylethhhhhh-fuuuuuuuaaaaaaackkkkkkk---”

Echoes filled the room, a squealing Shamir coming around Byleth’s cock, and as her clenched fists bit into the skin of his hips and the querulous walls of her clamped down on his unceasing pleasure, the two of them came as one. Byleth’s seed hit Shamir’s insides, and the warmth spurred her to find her own peak, and she rode that hard, spurting peak to her own end, panting and squealing as that interminable ache shot through her, peaking, peaking again, such a high-- until she had nothing left--

Shamir, hair sweaty, collapsed on Byleth under her, full of his cum, barely moving.

“Are you alright--”

“Shut up,” Shamir whispered, breathless, panting, sweaty, done-- “Shut up until you can go for round two.”

**Author's Note:**

> This was one of those things that came into my head after some fan art and wouldn't let go.
> 
> I've started a fe chat with some friends. Come stop by. https://discord.gg/PfQAkmb4RR


End file.
